Sampling Flashcards
Opportunity
Strength and weakness
The sampler selects participants from whoever is available at the time
S - Quick and easy
D - Can lead to a biased sample as not every memeber on the target population will be there
Volunteer
Sampling
This is where participants put themselves forwards to be put into the sample
S - Unbiased and most ethical
W - Less representative and lead to biased sample because volunteers will be more eager than the wider population making it invalid
Random
Sampling
Everyone from the target population must have an equal chance of being selected - just picking a few people is not actually random
S - Unbiased and helps control participant variables so it’s more valid
W - Time consuming and too many people with certain characteristics may be selected so not representive. Leading to sample error which leads to invalid conculusions
Stratified
Sampling
This sample is proportional representation of the target population
W - Time consuming and can lead to sample error if people refuse to take part leading to invalidity
S - Ensures that the sample is completely representative
Target population
The group of people that an investigation is concerened with or wishes to study and apply findings to
Sample
A small selection of people from the target population who are directly studied
The sample should repersent the nature of the target population
Biased sample
When the sample chosen is made of a particular type of person (e.g motivated people, people who don’t work at certain times) and so may not reflect the target population.
This means that we can’t rely on the same results happening again if the study is repeated to unrealiable
Sample error
When a sample differs in qualities from the target population it is trying to represent e.g too many men.
This means that the findings aren’t representative and therefor are not externally valid
